Learning to expose to the right can be one of the most valuable photography tips you learn as a photographer. ‘Exposing to the right’ is a technique for getting the maximum amount of image data in an image which is then adjusted to make its brightness correct.
When you expose to the right what you are doing is relying on using the camera’s histogram view and/or highlight alert to guide the exposure and avoid burning out important details or capturing a dark noisy image.
This is an especially useful technique for shooting landscape photography who want to preserver detail in bright clouds and avoid enhancing noise in dark shadows. The best results are achieved by shooting raw format files as these have the maximum amount of data for adjustment.
Why not just underexpose?
When the highlights in a scene are overexposed and burned out they are gone forever, they can’t be brought back by any amount of Photoshop adjustment.
To avoid having these featureless blobs of highlights in their images many photographers underexpose their images to some degree and then brighten them post-capture.
The problem with this approach is that image shadows tend to have more noise than brighter areas and brightening shadows brings out the noise.
This means if you capture a dark shot that needs brightening you are recording a noisy image and then make the noise more obvious.
Lighter parts of the image have a stronger signal and less noise, so provided that you don’t burn out anything important, it’s better to record a bright image and make it darker.